Calculating Wheel Fitment
11-10-2007, 01:32 AM
#1
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Calculating Wheel Fitment
I've seen post, after post, after post asking will this or that wheel fit. I assume there must be some calculation to figure fitment.
Can someone post how to calculate Wheel Fitment for the 3G? Please, help us help ourselves.
If you do post the calculation, a step-by-step calculation would help - I'm a little slow and if you skip steps I'll get lost.
Can someone post how to calculate Wheel Fitment for the 3G? Please, help us help ourselves.
If you do post the calculation, a step-by-step calculation would help - I'm a little slow and if you skip steps I'll get lost.
11-10-2007, 01:47 AM
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go to www.tirerack.com and click on fitment.
11-10-2007, 02:42 AM
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I did not find a "fitment" link, but did find the tech articles on "How We Know What Fits (I & II)", Offset, and Proper Fit.
None of them explain how to determine whether a given wheel fits or not. They just say Tire Rack figures it out for you.
Someone, somewhere, must know the available space in the wheel well of the 3G, the amount of clearance needed for the calipers and then the formula to figure if a given wheel will fit in that space and clear the caliper. That's what I'm looking for.
Maybe it's a dumb question and people "know" what fits based on conventional wisdom, experience and lucky guesses.
None of them explain how to determine whether a given wheel fits or not. They just say Tire Rack figures it out for you.
Someone, somewhere, must know the available space in the wheel well of the 3G, the amount of clearance needed for the calipers and then the formula to figure if a given wheel will fit in that space and clear the caliper. That's what I'm looking for.
Maybe it's a dumb question and people "know" what fits based on conventional wisdom, experience and lucky guesses.
11-10-2007, 04:18 AM
#4
i dont like tire racks fitment rules. they def. dont show you all your options..
basically... you are going to HAVE to have a bolt pattern of 5 x 114.3 (sometimes call 5 x 4.5)
you need a higher offset, since its a FWD drive vehicle. generally mid 30's - mid 40's.
Perfect center hub bore is 64.1 ..if you dont get the exact one, you get hubcentric rings
Width really shouldnt exceed 8.5.. obviously it can, but you face rubbing issues with tire widths over 245, especially when dropped. an 8.5" wheel with a 235 tire shouldnt rub at all, even when dropped as long as you stay in your offset range. There are obviously exceptions to all cases, which can be seen by the naked eye... (crazy rim depth etc,etc)
p.s. having brembo's or other 4POT calipers make things trickier. only a fraction of the available wheels for 3G TL's will fit one's with Big Brake Kits. 5AT TL's have a much, much larger selection
thats just wheels. tires are a whole other ball park
basically... you are going to HAVE to have a bolt pattern of 5 x 114.3 (sometimes call 5 x 4.5)
you need a higher offset, since its a FWD drive vehicle. generally mid 30's - mid 40's.
Perfect center hub bore is 64.1 ..if you dont get the exact one, you get hubcentric rings
Width really shouldnt exceed 8.5.. obviously it can, but you face rubbing issues with tire widths over 245, especially when dropped. an 8.5" wheel with a 235 tire shouldnt rub at all, even when dropped as long as you stay in your offset range. There are obviously exceptions to all cases, which can be seen by the naked eye... (crazy rim depth etc,etc)
p.s. having brembo's or other 4POT calipers make things trickier. only a fraction of the available wheels for 3G TL's will fit one's with Big Brake Kits. 5AT TL's have a much, much larger selection
thats just wheels. tires are a whole other ball park
11-11-2007, 12:51 PM
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We should start from OEM wheels: 17 x 8 5 x 114.3 +45 meaning: 17” diameter, 8” width, 5 holes at 114.3 mm (4.5”) diameter and +45 mm (1.772”) offset.
Diameter can go from (16”)17” to 20”. I would always recommend 17” wheels because they have smallest moment of inertia, consumes least energy to spin and stop, so they gives best performance. If they are lightweight too it helps even more. Rim diameter is related only to a tire profile in order to preserve outside diameter close to original.
Rim width can go up to 9” all around. It can be more at the back, but I would never recommend wider wheels at the back on a FWD car. Width is closely related to the offset:
W / 2 – O = A
W / 2 + O = B
W stands for width, O for offset, A for distance from wheel mounting surface to the wheel face and B for distance from wheel mounting surface to the wheel back.
OEM wheels: A = 56.6 mm = 2.228” and B = 146.6 mm = 5.772”.
A can go up to 80 mm or 3.2”. If it is more there is risk of fender rubbing, especially at the front. It greatly depends on tire width.
B can go up to 160 mm or 6.3”. If it is more rims will rub to the suspension.
Using this we can calculate maximum width for the given offset:
W = 2 * ( A + O )
W = 2 * ( B – O ) smaller of these two.
It is best to preserve factory offset because it is important factor of suspension geometry and handling.
W = 2 * ( 3.2 + 1.772 ) = 9.944”
W = 2 * ( 6.3 – 1.772 ) = 9.056” smaller is 9.056” so 9” would be maximum width with factory offset.
W = 9” O = 1.772” (45 mm ) gives:
A = W / 2 – O = 9 / 2 - 1.772 = 2.728” or 2.728 - 2.228 = 0.5” wheel face will be ½” closer to the fenders.
B = W / 2 + O = 9 / 2 + 1.772 = 6.272” or 6.272 – 5.772 = 0.5” wheel back will be ½” closer to the suspension.
Tire width can go up to 265 mm and should be mounted on a factory recommended rim width.
To calculate tire profile one can use this calculator: http://www.rims-n-tires.com/rt_specs...&text1=&text2=
Outside diameter should remain close to the OEM tires.
There is no calculation that can help determining Brembo calipers clearing. Only thing that can be done, besides trying it on a car, is measuring space between spokes and mount surface. Here is a picture with measures that would clear Brembo calipers:
Diameter can go from (16”)17” to 20”. I would always recommend 17” wheels because they have smallest moment of inertia, consumes least energy to spin and stop, so they gives best performance. If they are lightweight too it helps even more. Rim diameter is related only to a tire profile in order to preserve outside diameter close to original.
Rim width can go up to 9” all around. It can be more at the back, but I would never recommend wider wheels at the back on a FWD car. Width is closely related to the offset:
W / 2 – O = A
W / 2 + O = B
W stands for width, O for offset, A for distance from wheel mounting surface to the wheel face and B for distance from wheel mounting surface to the wheel back.
OEM wheels: A = 56.6 mm = 2.228” and B = 146.6 mm = 5.772”.
A can go up to 80 mm or 3.2”. If it is more there is risk of fender rubbing, especially at the front. It greatly depends on tire width.
B can go up to 160 mm or 6.3”. If it is more rims will rub to the suspension.
Using this we can calculate maximum width for the given offset:
W = 2 * ( A + O )
W = 2 * ( B – O ) smaller of these two.
It is best to preserve factory offset because it is important factor of suspension geometry and handling.
W = 2 * ( 3.2 + 1.772 ) = 9.944”
W = 2 * ( 6.3 – 1.772 ) = 9.056” smaller is 9.056” so 9” would be maximum width with factory offset.
W = 9” O = 1.772” (45 mm ) gives:
A = W / 2 – O = 9 / 2 - 1.772 = 2.728” or 2.728 - 2.228 = 0.5” wheel face will be ½” closer to the fenders.
B = W / 2 + O = 9 / 2 + 1.772 = 6.272” or 6.272 – 5.772 = 0.5” wheel back will be ½” closer to the suspension.
Tire width can go up to 265 mm and should be mounted on a factory recommended rim width.
To calculate tire profile one can use this calculator: http://www.rims-n-tires.com/rt_specs...&text1=&text2=
Outside diameter should remain close to the OEM tires.
There is no calculation that can help determining Brembo calipers clearing. Only thing that can be done, besides trying it on a car, is measuring space between spokes and mount surface. Here is a picture with measures that would clear Brembo calipers:
11-11-2007, 01:47 PM
#7
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^^
*THAT'S!!* what I'm talking about.
Great post. Thanks Mishar!
*THAT'S!!* what I'm talking about.
Great post. Thanks Mishar!
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11-12-2007, 08:05 AM
#12
Originally Posted by bforbrian
So i'm guessing 20x9 with 245/30/20 tires dropped will rub..
hey Brian...
You should have absolutely no issues with a 9" wide wheel running those tires...
... as always... the offset is a key feature... +40mm is very safe... those tires 245/30/20 are only 1.79% larger than the OEM 235/45/17... the plus sizing rule of thumb is within 3%...
However, I was running a tire that was 6% larger than OEM for over 2 years with absolutely no issues....
Good Luck...
11-12-2007, 09:38 AM
#13
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HERE is something I've posted before. The TL's OEM specs are already set up on the left. Adjust the right to whatever you want. How what you enter compares to OEM is in the chart at the bottom.
EDIT: same link mishar posted.
EDIT: same link mishar posted.
11-12-2007, 09:44 AM
#14
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mishar - what is the source of that pic? It doesn't seem like it's of a TL given the hub bore. However, Brembo/BBK clearance is something of interest to many, and is a number I've been looking for of late. If that pic is truly a TL, it answers the question perfectly.
11-12-2007, 12:27 PM
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Originally Posted by bforbrian
So i'm guessing 20x9 with 245/30/20 tires dropped will rub..
Originally Posted by chill_dog
mishar - what is the source of that pic? It doesn't seem like it's of a TL given the hub bore. However, Brembo/BBK clearance is something of interest to many, and is a number I've been looking for of late. If that pic is truly a TL, it answers the question perfectly.
11-12-2007, 01:02 PM
#16
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^^^64.1, but I guess that's splitting hairs with 63 (although, it would matter in real life). Nonetheless, thanks for the info...very usefull, indeed.
11-12-2007, 03:23 PM
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Whats your opinnion
I want to use a:
255/35 - 18 tire on a ----------18 x 9.5 rim with a 34 offset for the front
And a:
265/35 - 18 tire on a ----------18 x 9.5 rim with a 34 offset for the rear
Any clearence issues at stock or a drop of 1 to 1.5
255/35 - 18 tire on a ----------18 x 9.5 rim with a 34 offset for the front
And a:
265/35 - 18 tire on a ----------18 x 9.5 rim with a 34 offset for the rear
Any clearence issues at stock or a drop of 1 to 1.5
11-12-2007, 04:41 PM
#20
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Originally Posted by BLACKURA_NY
i dont think there is a 265/35 tire?? i could be wrong... u may have to go 265/30
There's lots of 'em (265/35/18). GY F1's; BS Pole Positions; Yoko Advan S4; Pirelli PZero; Michelin Pilots, etc.
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